1. Field of the Invention
The present invention relates to a plasma generation apparatus which irradiates a work to be processed such as a substrate with plasma, so that its surface can be cleaned or the surface quality can be reformed, and a work processing apparatus provided with this.
2. Description of the Background Art
A work processing apparatus is known which applies plasma to a work to be processed such as a semiconductor wafer. Thereby, it removes organic dirt from its surface, improves the surface's quality, etches the work, forms a thin film, eliminates a thin film, or conducts such another. A plasma processing apparatus is disclosed, for example, in Japanese Patent Laid-Open No. 2003-197397 specification. A plasma generation nozzle is used which includes an interior electric conductor and an exterior electric conductor which are concentric with each other. Between both electric conductors, a high-frequency pulse electric field (i.e., a microwave) is applied, and thereby, not an arc discharge but a glow discharge is produced so that plasma can be generated. In this apparatus, a processing gas from a gas supply source makes its way from the base-end side to the free-end side while whirling round between the interior and exterior electric conductors. Thereby, denser plasma is generated and radiates from a nozzle attached to the free end toward a work to be processed. This helps secure plasma with a high density under a normal pressure.
The above described prior art offers the superior plasma processing apparatus which is capable of obtaining highly-dense plasma under a normal pressure. Such a plasma processing apparatus can be used under a normal pressure, and thus, it is often installed in an area with people coming and going. Hence, in order to prevent a microwave from leaking out, a decision is made whether or not a microwave is leaking, by simulating such or using a measuring device practically in a designing stage or at the time of shipment from a factory.
However, such an apparatus may be vibrated or given a shock when an earthquake occurs or the apparatus is moved for reinstallation. Besides, if a person handles the apparatus carelessly, or if it gets out of order, that can make an impact on it. Such an impact may cause, beyond expectations, a microwave to leak. Therefore, another such apparatus is embodied which has the following structure. The apparatus main body is covered with a shielding frame body which screens out or attenuates a microwave. Even if a microwave leaks inside, it is prevented from leaking outside. However, even if the microwave does not leak out, then depending upon its power (i.e., microwave power), the inside leakage can give heat to some places of the apparatus main body. This may cause some parts of the apparatus to malfunction.